Stereo‐ and Site‐Selective Crotylation of Alcohol Proelectrophiles via Ruthenium‐Catalyzed Hydrogen Auto‐Transfer Mediated by Methylallene and Butadiene

Abstract

Iodide-bound ruthenium-JOSIPHOS complexes catalyze the redox-neutral CÀ C coupling of primary alcohols with methylallene (1,2-butadiene) or 1,3-butadiene to form products of anti-crotylation with good to excellent levels of diastereo-and enantioselectivity. Distinct from other methods, direct crotylation of primary alcohols in the presence of unprotected secondary alcohols is possible, enabling generation of spirastrellolide B (C9-C15) and leucascandrolide A (C9-C15) substructures in significantly fewer steps than previously possible.